EP0071917B1 - Electrical device, group of devices, or integrated circuit, the active part of which is placed on a metal support, and process for its or their manufacture - Google Patents

Description

The invention relates to an electrical component, a component group or an integrated circuit, the active part of which is applied to a metal carrier, in particular a surface acoustic wave filter with at least one input and output transducer on one side of an especially single-crystal piezoelectric body, as the active part, the is attached with its other side to the metal carrier to be electrically connected to ground, on one longitudinal side and in approximately the same plane running at least one connecting lug for this ground connection and further, electrically and mechanically separate connecting lugs for the power supply to and power dissipation from the active part Connecting wires are present, the active part, in particular the piezoelectric body, the metal carrier and the connecting wires are accommodated in a housing, the opening of which is closed with a plastic part and with adhesive and / or potting material and the connecting lugs by de n Protect the plastic part outwards. A surface acoustic wave filter of this type is known from EP-A-0 023 109.

Electrical components to which the present invention relates are passive and active components (resistors, capacitors, inductors, relays, diodes, transistors), component groups (printed circuit board-connected, interconnected passive and / or active electrical components), integrated Circuits and esp. Electrical surface wave filters.

Passive and active electrical components are well known. Likewise, component groups of the type explained above and integrated circuits.

Integrated circuits, e.g. B. Operational amplifiers are described, for example, in the Siemens book: "Components, technical explanations and characteristics for students", 2nd edition, 1977, on page 186.

Electrical surface acoustic wave filters of the type described are described, for example, in US Pat. No. 3,836,876, in DE-B-2,845,610 and in the magazine "Siemens Components", 18th Volume, Issue 4, August 1980, pages 167 to 169 and described.

The electrical surface wave filters in question here are those that can be installed vertically on a printed circuit board by the connection lugs protruding from the housing in the plane of the metal carrier body, as explained in the above-mentioned magazine "Siemens Components.

Another type of installation of surface acoustic wave filters in printed circuits provides that the terminal lugs of the metal carrier body are bent through an angle of 90 ° in one direction, so that the surface acoustic wave filter is arranged parallel to the surface of the printed circuit board after installation. Such a surface acoustic wave filter is drawn in the magazine "Siemens Components", 18th year, 1980, number 1, pages 44 and 45 and a housing for this is described in DE-A-3 011 730.7, published on October 1st, 1981.

Other embodiments of surface acoustic wave filters for horizontal installation are described in DE-A-2609884 (with the same priority as US-A-4 047 129) and in DE-B-2 610 172 (with the same priority as US-A-4 034 318).

On the other hand, it is well known to incorporate electrical components, with the exception of surface acoustic wave filters, into metal housings for the purpose of shielding, to which the present invention relates. As a rule, such metal housings consist of a cup of round or rectangular cross-section and a metal cover through which connecting pins - insulated by means of glass beads or other insulating materials - are passed. The connection to the ground of such housings takes place via a connecting pin which is galvanically connected to the cover and / or the cup of the metal housing.

The production of such shielding metal housings is very costly both in terms of the material and in terms of the work to be done and is therefore not applicable to electrical components which have to be produced inexpensively in very large quantities (a few million a year).

Electrical components, component groups and integrated circuits to which the present invention relates, in particular surface wave filters, are inexpensively built on practically flat metallic carrier elements, so-called spiders, the actual component, namely the active part of the electrical component, which, for example, is a Chip can be on a flat or specially shaped metal support, the z. B. has a trough-shaped recess is attached. The connections of the active component are connected to connecting lugs of the spider arranged on one side of the metal carrier by means of additional wires. The connecting parts are held together by means of a plastic part. One or more of the connection lugs can be galvanically connected to the carrier plate for electrical shielding and for mechanical stabilization. The fully assembled electrical component is covered to protect against mechanical and climatic influences with a plastic cup made of electrically non-conductive material and z. B. connected by potting compound. However, for the sake of better electromagnetic shielding, it is usual to use a metal housing instead of the plastic cup, which must be galvanically connected to the metal carrier of the active part.

The present invention has for its object to replace the metal housing with an easily manufactured plastic housing with the same good electromagnetic shielding.

To achieve this object, the invention provides that the housing is a plastic housing made of electrically conductive material and extends beyond the plastic part with its opening, and that the metal carrier at least at one end of its longitudinal side directed towards the plastic part merges into an additional ground terminal lug, which in its from Plastic part facing outward is galvanically connected to the protruding part of the plastic housing by means of conductive adhesive.

Since the galvanic connection between the metal carrier and the plastic housing takes place directly on the component and not only on the printed circuit board, the current loop is smaller and thus the shielding effect is better; and the electrical measured values of the component are largely independent of the measurement socket or the circuit board. Because the metal housing is not provided with a solderable connection leg, the material and processing costs are lower. In addition, the user of the electrical component does not have to take any special precautions in the printed circuit.

For a good connection between the earth connection lugs and the plastic housing, it is advantageous that the separating points produced on the earth connection lugs during their manufacture lie flush against the inner wall of the plastic housing or have a maximum distance of 0.2 mm from the inner wall.

To create a connection point between the terminal lug and the plastic housing, which can be produced without the terminal lug protruding, it is advantageous if the ground terminal lugs are immersed with their free end in a slot formed on the edge of the plastic housing and are galvanically connected to the plastic housing by means of conductive adhesive.

The invention further relates to a method for producing an electrical component, a component group or integrated circuit of the aforementioned. Type in which the metal carrier together with the connecting lugs are first punched out of a coherent metal strip in such a way that the cohesion of several metal carriers is ensured by a base strip with which the connecting lugs remain connected and by connecting pieces which, together with the connecting lug for the ground connection, connect the metal carrier and the connecting lugs result, it is guaranteed that the plastic part is formed around the inner connecting parts of the connecting lugs and around metal strips on the metal carrier to form the connecting pieces, before or after the active part is attached to the metal carrier and is accordingly electrically connected to the inner connecting parts by means of wires, then the Connectors are removed, the plastic housing is placed on the plastic part and connected to it with adhesive and / or potting material and sealed, and finally the connecting lugs are separated from the base strip in the appropriate length , wherein the transition from the metal strips of the metal carrier to the connecting pieces when punching out and removing the connecting pieces is shaped so that ground connection lugs are formed which are directed towards the inner wall of the plastic housing and butt against it after installation of the plastic housing or are immersed in slots in the housing edge or stand at most at a distance of 1 mm from it, after which the electrical connection between the plastic housing and the ground connection lugs is made by gluing using an electrically conductive adhesive.

A similar process is known from EP-A-0 061 648, published on October 6, 1982.

The invention is explained in more detail below and with reference to the drawings.

• Figur 1 einen teilweisen Schnitt längs der Linie I-I in Fig. 2 durch ein Bauelement, im vorliegenden Fall ein Oberflächenwellenfilter ;
• Figur 2 einen Schnitt gemäß der Linie 11-11 in Fig. 1 des gleichen Bauelementes ;
• Figur 3 ein in Fig. 1 strichliniert angedeutetes Detail 111 in geänderter Ausführung ;
• Figur 4 einen Ausschnitt, der das Herstellungsverfahren verdeutlicht ;
• Figur 5 ebenfalls einen Ausschnitt zur Erläuterung des Herstellungsverfahren mit einer anderen Form der ausgestanzten Metallelemente.

Show it :

• 1 shows a partial section along the line II in Figure 2 by a component, in the present case a surface acoustic wave filter.
• FIG. 2 shows a section along the line 11-11 in FIG. 1 of the same component;
• FIG. 3 shows a detail 111, shown in broken lines in FIG. 1, in a modified version;
• FIG. 4 shows a section which illustrates the manufacturing process;
• Figure 5 also shows a section to explain the manufacturing process with a different shape of the punched metal elements.

1 shows the active part of the electrical component, in the present case a piezoelectric single-crystalline plate - usually consisting of lithium niobate. The various transducer electrodes and coupler parts are not shown here for reasons of clarity.

The active part 1 is attached to a metal support 2, which is preferably provided with a trough-shaped depression for this purpose. The back of the active part 1 is connected to the metal carrier 2, for example by adhesive bonding.

On the long side 3 of the metal carrier 2 there are connecting lugs 4 to 8 which run in the same plane as the metal carrier 2. The connecting lug 4, which acts as a ground connection, is produced with the metal carrier 2 in one piece, i.e. H. its inner connecting part 32 merges into the metal carrier 2.

The inner part 32 of the connection lug 4 and the inner parts 33 to 36 of the connection lugs 5 to 8 are connected by wires 9 to 13 to the respective connection points of the active part 1. The wires can be thermocompression to the respective in a known manner to be attached to points. At the right end 19 and possibly also at the left end 20 of the long side 3 of the metal carrier 2, metal strips 37 and 38 are provided, which merge into earth connection lugs 21 and 22.

It is sufficient in itself if only such a ground connection lug 21 is present. However, there may also be a further ground connection lug 22, which may also be present in a further ground connection lug 22, which may also merge into a further ground connection lug 28 (therefore shown in dashed lines in FIG. 1), so that a ground connection is not merely via the connection lug 4, the inner connecting part 32 and the wire 13 is ensured, but that the metal carrier 2 can be connected to the ground via the metal strip 38, the ground connection lug 22 and the further ground connection lug 28.

The plastic housing 14 made of electrically conductive plastic is placed over the entire active part 1, the metal carrier 2, the lead wires 9 to 13, the inner connection parts 32 to 36 and a plastic part 16, for which purpose the plastic housing 14 has bends 15 adapted to the plastic part 16, so that a good and tight seal is guaranteed. The bends 15 merge into a part 18 protruding from the plastic part 16, so that a cavity is created which is either filled with adhesive material or - as in the present case (FIG. 2) - with potting compound 17, so that a hermetic seal results.

The connection lugs 4 to 8, 21 and 22 are firmly embedded in the plastic part 16.

In the left part of Fig. 1 it is shown that the ground terminal lug 22 abuts with its separating point 24 against the part 18 of the plastic housing 14 which projects beyond the plastic part 16 and that the galvanic contact between the metal carrier 2 and the plastic housing 14 is ensured by an adhesive connection 23 with electrically conductive adhesive is.

In the right part of Fig. 1, the arrangement of the ground terminal lug 21 opposite the protruding part 18 is shown before the adhesive connection is made. The separation point 25 is arranged at a distance 40 between the separation point 25 and the protruding part 18 by appropriate mutual dimensioning of the housing and arrangement of the earth connection lug.

In the exemplary embodiment according to FIG. 3, the plastic housing edge 26 is formed with a slot 46 into which the free end 47 of the ground connection lug 21 is immersed and is electrically connected to the plastic housing 14 by means of electrically conductive adhesive (not shown in the drawing).

There can be two ground connection lugs 21 and 22 at both ends of the metal carrier and connected to the plastic housing 14 by adhesive 23. However, such an adhesive connection 23 can also be produced only at one end.

The connection lugs 4 to 8 and possibly 28 are separated along the dividing line 42 from the metal strip. This process is related to the manufacturing method according to the present invention and is described below with reference to FIGS. 4 and 5.

An electrical component according to the invention is preferably produced by a method in which the metal carrier 2 together with connecting lugs 4 to 8 and possibly 28 are first punched out of a coherent metal strip 27 such that the cohesion of several metal carriers 2 by a base strip 29 remains with the Base strip 29 connected, and by means of connecting pieces 30 and 31, together with the connecting lugs 4, if necessary, 28, the strength of the metal strip is guaranteed for the ground connection.

The connection lugs 4 to 8 and possibly 28 (FIG. 5) are produced together in a stamping process in which the inner connection parts 32 to 36 are also formed. Characterized in that the inner connecting part 32 of the terminal lug 4 remains connected to the metal carrier 2 and the metal strips 37 and 38, which lead to the ground terminal lugs 21 and 22, are also connected to the metal carrier, and also by the connecting pieces 30 and 31 respectively entire metal strip 27 contiguous and can be used in an automatic device at the same time as a conveyor belt, for which the holes 43 and 44 serve for centering and the transport engagement.

During the punching process, it is ensured that the ground connection lugs 21 and 22 arise in such a way that they later lie with their separating points (see FIG. 1) on the plastic housing 14 or are arranged at the specified maximum distance therefrom.

The plastic part 16 is formed around the inner connecting parts 32 to 36 of the connecting lugs 4 to 8 and around the metal strips 37 and 38 on the metal carrier 2, which lead to the connecting pieces 30 and 31.

Before or after the active part 1 is attached to the metal support 2. So that undesirable vibrations are suppressed, particularly in the case of harmonic surface filters, two spacer knobs are arranged in the trough-shaped recess 39 of the metal carrier, for example as described in DE-OS 2 845 610.

The wires 9 to 13 shown in FIG. 1 or other transition connections to the inner connection parts of the connection lugs are then attached for the purpose of electrical connection, for example by thermal compression, as is known per se.

Then the connectors 30 and 31 are removed so that separation points 25 are formed (Fig. 1).

The plastic housings 14 are then placed on the arrangements prepared in this way during the automatic production process, and - as described above - the adhesive connection 23 is produced. The adhesive connection 23, however, the closure can also be produced by means of adhesive and / or potting material.

Already at this time or also after the separation of the connecting lugs 4 to 8 and possibly 28 along the line 42, the closure is produced by means of adhesive and / or potting material.

For reasons of the use of electrical components according to the present invention in automatic assembly devices for printed circuits, it may be advantageous to leave several such electrical components on the base strip 26 and to carry out the separation along the line 42 only when the printed circuit is being assembled.

Claims (5)

1. An electrical component, component group or integrated circuit, the active part (1) of which is placed on a metal carrier (2), in particular a surface wave filter having at least one input- and output transformer on the one side of a piezo-electric body, in particular a monocrystalline piezo-electric body, as the active part (1), which body has its other side fastened to the metal carrier (2) which is to be electrically connected to earth, and on whose one longitudinal side (3) and extending in the same plane, are arranged at least one connecting lug (4) for the earth connection and further, electrically and mechanically separated connecting lugs (5 to 8) for the current supply to and the current discharge from the active part (1) through connection wires (9 to 12), where the active part (1), (in particular the piezo-electric body) the metal carrier (2) and the connection wires (9 to 15) are accommodated in a housing (14), the opening (15) of which is sealed by means of a synthetic resin part (16) and with adhesive and/or sealing material (17), the connecting lugs (4 to 8) projecting outwards through the synthetic resin part (16), characterised in that the housing is a synthetic resin housing (14) made of an electrically conductive material and projects above the synthetic resin part (16) at its opening (15) ; and that at least at one end (19, 20) of its longitudinal side (3) directed towards the synthetic resin part, the metal carrier (2) passes over into an additional earth connecting lug (21, 22), which in its portion which is turned outwardly from the synthetic resin part, is electrically conductively connected to the protruding part (18) of the synthetic resin housing by means of conductive adhesive (23).

2. An electrical component as claimed in Claim 1, characterised in that at least one of the earth connecting lugs (21, 22) is so dimensioned that its separation point (24, 25), which is produced during production, is flush with the inside wall of the synthetic resin housing (14) or has a maximum distance of 1 mm from the inside wall.

3. An electrical component as claimed in Claim 1 or Claim 2, characterised in that at least one of the earth connecting lugs (21, 22) has its free end (47) dipping into a slot (46) which is formed at the edge (26) of the synthetic resin housing and is electrically conductively connected to the synthetic resin housing by means of a conductive adhesive.

4. An electrical component as claimed in one of Claims 1 to 3, characterised in that at least one earth connecting lug (21, 22) is provided with an extension which serves as a further earth connecting lug (28) for earth connection.

5. A process for the production of an electrical component, component group or integrated circuit as claimed in one of Claims 1 to 5, wherein the metal carriers (2) together with the connecting lugs (4 to 8 and 28) are first punched from a continuous metal strip (27) in such manner that the connection together of a plurality of metal carriers (2) is ensured by the base strip (29), to which the connecting lugs (4 to 8 and 28) remain connected, and by connection pieces (30, 31), which, together with the connecting lug (4) for the earth connection, form the connection between the metal carrier (2) and the connecting lugs (5 to 8 and 28), whereupon the synthetic resin part (16) is formed around the inner terminal parts (32 to 36) of the connecting lugs (4 to 8) and around metal strips (37, 38) on the metal carrier (2) to the connection pieces (30, 31), the active part (1) being previously or subsequently secured to the metal carrier (2) and correspondingly electrically connected to the inner terminal parts (32 to 36) by means of wires (9 to 13), the connection pieces (30, 31) are then removed, the synthetic resin housing (14) is placed on the synthetic resin part (16) and connected and sealed thereto by adhesive and/or sealing material (17) and the connecting lugs (4 to 8 and 28) are finally separated from the base strip (29) at corresponding lengths, wherein, during the punching process and the removal of the connection pieces (30, 31), the junction of the metal strips (37, 38) of the metal carrier (2) to the connection pieces (30, 31) is so formed that earth connecting lugs (21, 22) are produced which are directed towards the inner wall of the synthetic resin housing (14) and, when the synthetic resin housing (14) has been set up, are butt-jointed to said inner wall or dip into slots on the edge (26) of the housing, or are at a maximum distance of 1 mm therefrom, whereupon the electrical connection (23) between the synthetic resin housing (14) and the earth connecting lugs (21, 22) is effected by adhesion using an electrically conductive adhesive.

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